1. Field
The present disclosure relates generally to rotorcraft and, in particular, to the rotor blades of a rotorcraft. Still more particularly, the present disclosure relates to an apparatus and method for tuning the vibratory response of a rotor blade using a tuning object having a plurality of channels.
2. Background
Rotorcraft, such as, for example, without limitation, helicopters, may use rotor blades to generate lift. In some cases, the lift generated by these rotor blades may be varied by changing the twist of each of the rotor blades. However, increasing the twist of each of these rotor blades may cause an increased vibratory response. In other words, increasing the twist of the rotor blades may cause the rotor blades and/or other portions of the rotorcraft to vibrate more than desired. These vibrations may have undesirable effects on the rotorcraft and/or its occupants.
Some currently available solutions for reducing this vibratory response include adhesively bonding one or more objects of known mass to each of the rotor blades at one or more specific locations within the rotor blade. These objects may be referred to as tuning masses or, in some cases, tuning weights. The amount of mass added to a rotor blade and the location at which that mass is added may be selected such that the vibratory response of the rotor blade is “tuned” to within selected tolerances.
As one illustrative example, a plurality of cylindrically shaped objects, each having the same mass, may be bonded to the nose area of a rotor blade. The nose area may be near the leading edge of the rotor blade. However, the number of objects needed to achieve the desired reduction in vibratory response may be greater than desired. For example, without limitation, keeping track of these objects during installation of these objects may become more and more difficult as the number of objects used increases. Further, as the number of objects needed increases, the manufacturing of these objects may become more time-consuming and/or require more effort than is desirable.
In some cases, a single tuning mass may be adhesively bonded to the rotor blade. However, the shear stresses formed within the adhesive bond between the tuning mass and the rotor blade may be greater than desired when the tuning mass is installed at certain locations within the rotor blade. These shear stresses may cause undesired inconsistencies to occur within the adhesive bond and/or may cause the adhesive bond to separate from the tuning mass and/or the rotor blade. Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above, as well as other possible issues.